We are studying the gelation kinetics of deoxyhemoglobin S, using rheological techniques. The method involves oscillation of a magnetic sphere in the sample, under the influence of a sinusoidally varying magnetic force. Measurement of the amplitude ratio and phase shift gives values of both viscosity and elasticity as a function of time. Gelation is initiated by carrying out a rapid temperature jump. Kinetic parameters for the lag and gelation phases are being obtained as a function of final temperature, Hb concentration, pO2 and other parameters. The influence of various gelation inhibitors on the kinetics are also being studied.